Sustainable disassembly line balancing model based on triple bottom line

End of life (EOL) phase of a product is receiving more attention due to increase in environmental concerns, and many studies have been conducted for value creation in EOL, focusing on concepts as remanufacturing, reuse and recycling in sustainable production manner. This study especially focuses on one of global problem, e-waste. To minimise the amount of wastes and maximise recovered materials from EOL, disassembly is one of the most important concept, associated with reuse, and balancing disassembly line in an optimal way is essential for organisations. In disassembly line balancing (DLB), not only precedence of tasks, but also risk criteria related to environment and human safety should be considered for sustainability. The aim of this study is to propose a model based on triple bottom line (TBL) dimensions, i.e. human safety, environmental safety and business criteria. To achieve sustainability in DLB, and for risk assessment in sustainable DLB, it had been decided to use a multi-criteria method, i.e. TODIM, acronym in Portuguese of ‘Tomada de Decisão Iterativa Multicritério’. The proposed model included 22 disassembly criteria categorised under TBL dimensions, which are derived from the literature. Implementation of the study was conducted for computer disassembly processes, and as a result of the study approximately 12% an improvement in cycle time was succeeded. In the long run, the integration of sustainability in disassembly operations may contribute to the competitive advantage of the company in terms of differentiation and corporate image by achieving business, environment and human targets simultaneously.     

Learning and revision in cognitive robotics disassembly automation

Disassembly is a key step for an efficient treatment of end-of-life (EOL) products. A principle of cognitive robotics is implemented to address the problem regarding uncertainties and variations in the automatic disassembly process. In this article, advanced behaviour control based on two cognitive abilities, namely learning and revision, are proposed. The knowledge related to the disassembly process of a particular model of product is learned by the cognitive robotic agent (CRA) and will be implemented when the same model has been seen again. This knowledge is able to be used as a disassembly sequence plan (DSP) and disassembly process plan (DPP). The agent autonomously learns by reasoning throughout the process. In case of an unresolved condition, human assistance is given and the corresponding knowledge will be learned by demonstration. The process can be performed more efficiently by applying a revision strategy that optimises the operation plans. As a result, the performance of the process regarding time and level of autonomy are improved. The validation was done on various models of a case-study product, Liquid Crystal Display (LCD) screen.     

一例带电水冲洗触发的220kV避雷器爆炸事故分析

对一例220 kV金属氧化物避雷器在带电水冲洗后发生爆炸故障的原因进行了分析。通过对完好避雷器和故障避雷器进行解体和对比分析,发现故障避雷器下节顶部压力释放装置内部的密封胶圈发生凹陷变形。最后,对该类事故提出预防措施。     

A fast branch,bound and remember algorithm for disassembly line balancing problem

In recent years, the interests of disassembly line have increased owing to economic reasons and the increase of environmental awareness. Effective line can provide many advantages in terms of economic aspect and it facilitates competition the companies with others. This study contributes to the relevant literature by a branch, bound and remember algorithm for disassembly line balancing problem with AND/OR precedence. The proposed exact solution method employs the memory-based dominance rule to eliminate the reduplicated sub-problems by storing all the searched sub-problems and to utilise cyclic best-first search strategy to obtain high-quality complete solutions fast. In this paper, minimising the number of stations is taken as the performance measure. The proposed methodology is tested on a set of 260 instances and compared with the mathematical model using CPLEX solver and five well-known metaheuristics. Computational results show that the proposed method is capable of obtaining the optimal solutions for all the tested instances with less than 0.1?seconds on average. Additionally, comparative study demonstrates that the proposed method is the state-of-the-art algorithm and outperforms the CPLEX solver and metaheuristics in terms of both solution quality and search speed aspects.     

不确定环境下回收发动机拆卸调度方法

针对再制造系统中回收发动机的不确定因素,研究面向再制造拆卸的调度问题。首先为了减少再制造拆解过程中不确定因素的影响,采用模糊综合评价法进行了回收质量等级划分;然后采用双重模糊变量描述了回收发动机质量状况差异及拆解时间的不确定性,建立了基于双重模糊机会约束的再制造拆解车间生产调度问题模型;应用双重模糊模拟技术产生输入和输出数据,利用神经网络逼近模型的不确定函数,将训练后的神经网络嵌入遗传算法求出优化结果。通过仿真实例验证了该混合智能优化算法解决双重不确定拆卸调度问题的有效性和合理性。     

浅埋大跨公路隧道穿越富水软弱土层施工关键技术

以厦漳公路(厦门段)东孚隧道施工为例,介绍了?229大管棚跟管钻进咬合相接加固技术+十字交叉隔壁后拆式开挖技术在浅埋富水软弱土层隧道开挖过程中的应用;同时利用TGMIS动态智能化监测系统对施工沉降状况进行了数据采集、分析及处理,使围岩变形得到控制,顺利通过了浅埋软弱土层段掘进施工。     

Integrated multi-layer representation and ant colony search for product selective disassembly planning

Selective disassembly plays an important role in product life cycle to meet requirements of the product repairing, reusing and recycling. An efficient disassembly plan is essential to minimize processing time in product maintenance for cost saving. This paper introduces a method for integration of the multi-layer product representation and the optimal search in product selective disassembly planning. The multi-layer representation is based on the product structure formed in product design. The method enables an efficient search for the disassembly sequence. Unlike the existing product representation methods, the multi-layer representation is a dynamic product data model integrated with an ant colony search process for a near optimal solution. Industrial applications have proven the method effectiveness.     

Waste electronics and electrical equipment disassembly and recycling using Petri net analysis: Considering the economic value and environmental impacts

The Industry Council for Electronic Equipment Recycling (ICER) has published estimates of waste generation based on both assumptions and analysis regarding the relationship between the market sales of Electrical and Electronic Equipment (EEE) in a given year and the expected lifetime of products as well as by employing market saturation factors. Waste EEE (WEEE) has an adverse impact on the environment. Therefore, it is important to reduce the quantity of WEEE through recycling. While attempting to improve the recycling rate of WEEE by enhancing the disassembly processes, two issues must be considered simultaneously—economy and safety. In this paper, a Petri Net (PN) based analysis approach is proposed to deal with the disassembly and recycling problems in End-Of-Life (EOL) WEEE. By using the PN analysis, the optimal tradeoff between the cost and environmental effectiveness of the disassembly processes is determined. A case study is used to illustrate the proposed analysis method.     

Modular product platform configuration and co-planning of assembly lines using assembly and disassembly

Formation of products platforms is carried out during the planning stage and very often separately from the planning of corresponding assembly lines. There is a dearth of literature which considers the different aspects of fully integrating platform design, product family formation, assembly line design, delayed product differentiation, and new concepts of mass customization. A Modular Product Platform Configuration model which uses assembly and disassembly for configuring product variants and Co-Planning of products platforms (MPCC) and their assembly Lines is presented. It is used to co-plan the common platform components and the associated product families simultaneously with the planning of its corresponding mixed-model assembly line. Using both assembly and disassembly to customize the product family platform in order to generate product variants is not commonly discussed in literature. It is defined as the formation of platforms for use to derive multiple products by including many components not shared by every product. The platform is then customized by assembling or disassembling components to form different product variants. The model is formulated using mixed integer mathematical programming to minimize the number of assembly stations and cycle time. Two case studies are used for verification and demonstration. They illustrated the ability of the MPCC model to integrate the planning of product platform, product families and the number of assembly stations required to assemble and disassemble components from mass-assembled product platforms to derive new product variants.     

免拆卸水泥复合模板-结构混凝土柱的轴心受压性能研究

通过对二根柱试件(一根免拆卸模板混凝土柱,一根普通混凝土柱)的试验,研究了免拆卸模板混凝土柱在单调荷载作用下的基本力学性能,包括破坏形态、极限承载力、柱侧混凝土应变、受力钢筋应变等,对免拆卸模板-结构混凝土柱与普通混凝土柱的受力性能进行了对比.实验结果表明:采用现行规范计算免拆卸模板-结构混凝土柱的极限承载力具有较高的...